The invention relates to the development, creation, and use of software for process control, specifically ActiveX controls that are OPC compliant.
Process control relates to the control of the parameters of a process, such as a manufacturing process. The parameters can include duration, temperature, pressure, speed, quantity, and/or direction of motion, for example. In other processes, such as in those performed in the course of using and maintaining information systems, management systems, and the like, the parameters may relate to paper documents or machine-readable media, or to intangible quantities such as units of time or units of money such as a credit limit, or enunciation of a result such as may be accomplished by a printer, a visual display module, or an aural signal. Process control systems can be used to help manage production, monitor and maintain equipment, and/or perform business functions such as maintaining inventory records, performing accounting, and tracking sales.
Manufacturers generally purchase equipment for performing each of the necessary manufacturing tasks, rather than building all of the necessary equipment. The equipment often is supplied by a number of different vendors. These diverse pieces of equipment often are not designed to communicate with each other. Also, certain machines may be numerically controllable, and may have the capability of being connected individually to a computer. Typically, however, different known machines do not utilize electrical control signals of the same format.
Connecting multiple machines of several different types, which may have been built by different vendors, into a single unified process control system can be a difficult task. Many equipment suppliers employ proprietary data communication systems or formats. Standardized data communication formats and protocols are sometimes agreed upon in an industrial setting, but years may pass before the majority of equipment manufacturers implement the standards in the machines they sell. There are competing and incompatible standardized data communication protocols that have been implemented by various companies or groups of rival companies.
A manufacturer of processing machinery generally wants to provide to customers not only a machine but also the capability of connecting the machine into a process control system that can improve the productivity of the machine. In order to make this interconnection process as simple and as convenient as possible for the purchaser of the machine, the manufacturer can supply software that allows the interconnection to be done simply by installing the software on a control computer and hooking up the appropriate wiring. A software development toolkit according to the invention eases the task of connecting a computer and a machine to allow them to communicate according to a standard communication protocol for process control. The toolkit allows a user to produce the necessary real-time interactive control and communication software objects, such as ActiveX controls, that are used in connecting and interoperating the control computer and the machines.
In one aspect, the invention features a method of creating one or more real-time interactive control and communication software objects for use in connection with a computer and a machine which communicate according to a standard communication protocol for process control. The method comprises producing a display module which displays a graphical representation of a user interface of the machine on a display of the computer, and associating the graphical representation of the user interface with at least one control signal. The method further comprises producing a control module to examine the graphical representation of the user interface and the associated control signal, and producing a communication module to communicate the associated control signal using the standard communication protocol for process control. The method also comprises producing a framework module to interconnect functionally the display module, the control module, and the communication module. The framework module, the display module, the control module, and the communication module are merged to create the one or more real-time interactive control and communication software objects.
Embodiments of this aspect of the invention can have the following features. For example, the standard communication protocol can be the Object Linking and Embedding (xe2x80x9cOLExe2x80x9d) for Process Control (OPC) protocol. The real-time interactive control and communication software objects can be objects insertable using standard object insertion techniques, such as ActiveX control objects. The control module can examine the graphical representation of the user interface and the associated control signal periodically, or it can examine the graphical representation of the user interface and the associated control signal when a change in the graphical representation of the user interface or a change in the associated control signal is detected. Pre-fabricated software modules can be used in the method, including such modules as a pre-fabricated software image of a graphical representation. The software which is generated by the method can be compiled software or interpreted software.
In another aspect, the invention involves a computer-readable medium on which is stored a computer program for creating one or more real-time interactive control and communication software objects for use in connection with a computer and a machine which communicate according to a standard communication protocol for process control. The computer program comprises instructions, which, when executed by a computer, perform the steps of producing a display module which displays a graphical representation of a user interface of the machine on a display of the computer, associating the graphical representation of a user interface with at least one control signal, and producing a control module to examine the graphical representation of the user interface and the associated control signal. The computer program further comprises instructions, which, when executed by a computer, perform the steps of producing a communication module to communicate the associated control signal using the standard communication protocol for process control and producing a framework module to interconnect functionally the display module, the control module, and the communication module, and merging the framework module, the display module, the control module, and the communication module to create the one or more real-time interactive control and communication software objects.
Embodiments of this othe aspect of the invention can have the following features. For example, the communication module can communicate using the Object linking and embedding for Process Control (OPC) protocol. The real-time interactive control and communication software objects can be objects insertable using standard object insertion techniques, such as ActiveX control objects. The control module can examine the graphical representation of the user interface and the associated control signal periodically, or when a change in the graphical representation of the user interface or in the associated control signal is detected. The program can utilize a pre-fabricated software image of the graphical representation. The merge module may compile and link the framework module with the display module, the control module, and the communication module or it may interpret them in order to create the one or more real-time interactive control and communication software objects.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.